Wavelength-dependent J–V characteristics of CuIn1-x Ga x (S,Se)2 solar cells and carrier recombination

We propose here a new experimental setup, allowing the probing of CuIn 1- x Ga x (S,Se) 2 (CIGSSe) solar cells under varying wavelengths and intensities, using a supercontinuum laser. The setup is used to study the effects of potassium treatment on CIGSSe cells. Their J – V characteristics are taken at 500 nm and 950 nm, at intensities from 5 × 10 14 photons cm −2 s −1 to 4 × 10 16 photons cm −2 s −1 . The untreated sample's response shows strong dependence on the exciting wavelength. After potassium treatment, this dependence is a lot less important. Using simulation, we show that this difference can be explained by a reduction in the defect density in the depletion region.